Sharks are already scary enough, what with their razory teeth and evolutionarily honed hunting mojo. But this monster has a retractable jaw. A retractable effing jaw. You're welcome, nightmares.

The only thing keeping the Mitsukurina Owstoni, as it's known in its native Japan, from taking up permanent residence in my fear cabinet is that this incredibly rare — once even thought to be extinct — shark is only 1.3 meters long.